Atriplex watsonii is a sprawling plant that exhibits much variation in leaf size, as attested in the clearly staminate type collection, Palmer 334, wherein the range in size is from 5-25 × 2.5-11 mm wide. Although typically placed adjacent to A. matamorensis, the other dioecious perennial, the two taxa are probably not closely allied. The broader-leaved phases simulate closely A. leucophylla, with which it is sometimes confused, and perhaps the relationship lies in that direction, but it closely simulates A. californica, with which it is probably most closely allied.